Squeaking brakes usually mean you need to buy new brake pads. However, there are also possible other causes of squeaking or unpleasant noises from the brake system of a passenger car. When the car stops, the cause of the noise could be contamination, improper installation, or worn or dislocated brake discs.
Squeaking of pads during braking can be caused by dust particles that get between the disc and the pad. The reason for squeaking can also be a metal plate of the pad, which indicates that the friction lining is running out.
Sometimes the issue is minor, and the squeal is brief. Simply put, particles of sand or other contaminants collected during out-of-town driving may have gotten between the disc and the pad. After a few braking sessions, they wear off completely, and everything returns to normal. However, you need to know that such an option means both squeaking brakes when braking lightly and harder. Sometimes, dust can also cause a slight vibration of the steering wheel while driving. This is one of the characteristic symptoms of the Volkswagen Group's four-wheel drive, which you can find on the last sold cars list, for example.
Some brake pads have so-called wear sensors. These are metal plates that begin to make metallic noises during braking when the friction layer is already severely worn off. This happens after tens of thousands of kilometers since the last pad replacement (from 30 to 70 thousand kilometers, depending on the quality of the pads and breaking style). Sometimes pads also have electronic brake pad wear sensors. These are nothing more than wires protruding from the brake pad.
The electronic brake pad wear sensor is plugged into the electrical system of the car. In this case, you will be informed of pad wear before squealing brakes appear. You will be alerted to the need for a workshop appointment by the illumination of a warning light and a possible message displayed on the onboard computer. And while such a solution may seem highly advanced, today it is already standard. Even cars as old as a dozen years have them.
If your brake pads are worn out and your car squeals, it's a good idea to replace them as soon as possible. If we delay, the friction layer on the pad will be destroyed. Then the metal part of the brake pad will rub against the brake disc. This will make both pads and discs eligible for replacement. However, this is not the end of the story. In extreme cases, both the pad and the disc may break. This means that your vehicle will lose the ability to brake on one of the wheels.
There can be many reasons for squeaking brakes. Among the most common are:
- wear and tear of individual system components,
- poor fit (for example, by improper installation),
- differences in the materials from which they were manufactured (too-hard pads matched with too-soft discs),
- wear and tear (abrasion of working surfaces),
- change in geometric characteristics (reduction in thickness, dislocation, uneven wear, formation of grooves, etc.).
On this point, we have a small piece of advice for you. The sounds generated during brake system operation are not a natural symptom - unless your car is equipped with ceramic discs that are not reheated. However, the problem is not due to a lack of proper "slip". Applying WD40 to squeaky brakes is therefore not the best idea. Much better is to visit an auto repair shop and look for the natural causes of the problem.
Drum brakes squeal due to corrosion that occurs due to maintenance failures. Squeaking is primarily caused by the shoe's self-adjusting backlash mechanism. The solution to the problem is to purchase a repair kit or replace the set of brakes with new ones. To avoid a similar malfunction in the future, about once a year you should take the drums apart, clean them thoroughly, and check their condition. If you don't have enough technical knowledge, ask a mechanic for help in this regard.
Of course, squealing drum brakes can also indicate wear on the shoes or the working surface of the drum itself. However, the list of potential faults does not end there. Sometimes the cause of the problem is mistakes made by the mechanic when servicing the drums, or simply dirt that collects inside. You may find that your car's improperly installed jaws are chipping off particles that are bouncing off the drum or getting under the working surface.
Sometimes the problem with squealing brakes is not about their operation at all. This happens when you notice squealing brakes while driving. And that usually means one scenario. During the recent rainfall, you first braked hard a few times, warmed up the discs, and then drove into a puddle. The metal was immersed in cold water, so it went through a hardening process, and the discs simply warped. Because of this, they begin to rub against a properly installed pad while driving. Therefore, disturbing sounds and, for example, vibrations felt on the steering wheel.
You already know why brakes squeal while driving. You should also know how to deal with the problem. Unfortunately, we do not have good information for you. Regardless of the condition of the discs and pads, you must decide to replace a set. Otherwise, brake squealing will remain. The discs will not spontaneously return to their original shape under the influence of temperature, nor will they straighten out. Instead, you will experience more and more vibration, and the braking system may lose its efficiency.
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